Combined conduit-clamp and knock-out disk.



W. A. BONNELL. COMBINED GIONDUIT CLAMP AND KNOCK OUT DISK. APPLICATIONFILED NOV, 21, 1908.

921,585 Patented May 11, 1909.

Qvmm oeo UNITED STATES. PATENT OFFICE. WILLIAM A. BONNELIJ, OF NEW YORK,N. Y-., ASSIGNOF. TO HATTIE W. BONNELL, OF BROQKLYN, NEW YORK.

' COMBINED COND UIT-CLAMP AND KNOCK-OUT DISK.

No.'921,5s5.

Specification of Letters Patent.

. Patented May 11, 1909.

.{tpplication filed November 21, 1908. Serial fio. 463,773.

T 0 all whom it may concern: I Be it known that 1, WILLIAM A. B NNELL,

a citizen of the United States, residing at the city of New York, countyand State of New York, have invented certain new and useful Improvementsin a Combined Conduit-Clamp 8.I1(l Knock-Out Disk, of which thefollowing clamping plate and so-called knock-out disk,

which will be economical to manufacture and will save time in theassembling of the box,-

clamp and disk.

In constructions of this character hereto-f the conduits'in place in thebox, andthe knock-out disks which are intended to close such of theconduit openings or sockets not -in-use,in separate parts. Suchconstruction involves the separate molding of the plates and disks andalso the assembling of two parts upon the box instead of one. To obviatethese objections, I form the clamping late and knock-out disk inonepiece wherey said parts may be assembled upon the box in oneoperatlon, and a further advantage resulting from this construction isthat when the knock-out disk is broken out, the. roughened edgeor lipleft thereby upon the edge of the clamping disk forms a gripping edgeorface to securely engage the conduit. 'With these objects in view, myinvention consists in the construction and arrangement of parts a.preferredembodiment of. which is illustrated in the accompanyingdrawings, in

. which,

,Figure 1 is a plan view of the rear side of an outlet box, showing aconduit clamped in one of the sockets thereof. Fig. 2 is a sectionalview on the line 90-20 Fig. 1. Fig. 3 is a view similar to Fig. 2,showing the combined clamping plate or knock-out disk in positionclosing one of the conduit sockets. Fig. 4 com rises a plan and edgeview of the combined 0 amping plate and knock-out disk,

and, Fig. 5 is a view similar to Fig. 4, show ,ing the clamping plateafter the knock-out disk has been broken off.

In the embodiment of myinvention herein selected for illustration, 1indicates an outlet 'box of usual circular construction and havingarranged around its perimeter aplurality (here, four) of conduitreceiving sockets or bushingsZ, which, as shown in Figs. 2 and 3,

project into the interior of the box and are sired manner as by a setscrew in said sleeve.

Adjacent each conduit bushing are arranged clarnping plate receivingdepressions 6, having slots 7 at the bottom for the passage of theclamping screw 7 which serves tomove the'clamping plates to holdingposition against the condults. The rear surface 8 of each clamping-platereceiving depression is inclined to c'o-act with corresponding inclinedsurfaces 9, upon the rear ends of the clamping plates 10, whereby saidplates will be moved to cla screws'are tightene up.

, Each of the clamping plates 10 has formed integral therewith 'at itsforward end a knock-out disk 11 which is made comparatively thin, sothat it may be readily broken out. .As illustrated in Fig. 3, theclamping plate when in position adjacent an empty ushing serves with itsintegral disk 11 to- W hen it is desired to inclose said bushing. sert aconduit in one of the bushings, it is only necessary to break out theknock-out disk, closing the same, thus leaving a free passage for theconduit. When the disk is so broken out, the lineof cleava e thereofwith the corres onding clampin p ate leaves a roughened e ge 12' on saidp ate which is adaptedto securely engage the conduit. The junctionbetween the plate and disk furthermore is formed on a curve of aproximately the radius of the conduit to e clam ed whereby the brokenedge 12 when the p ate is in position against the conduit, willserve toembrace the latter, and inasmuch as the conduit is usually formed of oneor more spi bushing. The heads 14 of the clamping screws 7 by which theclamping plates are secured within their depressions, are located ingposition when the in the interior of the box, so that they may i criededge of raw metal will be left at the be readily reached by a screwdriverwhen the box is secured in position. By reason of the fact thatthe clamping plates are located above the rear surface of the box, andonly the heads of the clamping screws project within the interiorthereof, ample room is afforded within the interior of the box formanipulation of the, electric cables or wires. A further advantage offorming knock-out disks integral with the clam )in-g plate lies in thefact that when said disks are broken away a raw ed e of metal is leftwhich when in contact Wit the conduit, serves effectively to ground thesame, Which is a highly desirable feature in devices of this character.

While I have. herein shown a particular embodiment of my invention, itis to be understood that the same may be altered in detail and relativearrangement of parts with- 4 out departing from the spirit or scopethereof.

What I claim is:

1. Iii a device of the character described, a clamping plate having aninclined rear wall and having a knock-out disk formed integral therewithat its forward end and so arranged that when said disk is broken away, aroughline of cleavage.

2. In a device of the character described, a

end and having a knock-out disk formed integral with said end at theclamping edge of said plate. I

3. In a device of the character described, a clamping plate having aninclined forward end and having a knock-out diskformed 1ntegraltherewith at said end and slightly below the outer surface of said plateand so arranged that when severed from said plate, a

clamping plate having an inclined forward rou hened edge of raw materialwill be left to form the conduit-engaging edge of said ate.

p 4. In a device of the character described ,a clamping late having itsforward end of reduced thic ness and having a'knock-out disk formedintegral with said end and so. arranged that when said disk is brokenaway a roughened edge of raw metal will be left at the line of cleavageforming a clamping edge for said plate.

WILLIAM A. BONNELL; Witnesses:

R. W. PAWELL, CHAS A. PEARD.

